I have spent the last decade building large-scale systems at eBay and Google -- and talking publicly about it -- and this presentation is about why a startup should completely ignore what I said! In an early-stage startup, it is not only not worth architecting for a future of massive scale; it is actively counterproductive. This presentation from the SF Startup CTO Summit outlines the common architectural evolution of a startup through the search, execution, and scaling phases, and discusses the appropriate technologies and disciplines at each phase. It ends with some real-world examples from eBay, Twitter, and Amazon to illustrate the point.